Process of producing a porous cementitious article



product is of extremely Patented Mar. 29, 1927.

UNITED STATES ALEXANDER T. SCHENCK, OF SEATTLE, WASHINGTON.

No Drawing.

This invention relates to a process in the producing of cement andcementitious products whereby the material is so handled and treatedduring the mixing and molding ofthev particular article that theresultant for the cubical contents as compared with the weight of theordinary cement mixture when producing a similar product.

In cementitious products as heretofore produced the material has beenclose grained and impervious to air and moisture and where lightness ordead air spaces were desired such have been specifically molded into thearticle.

provide the cementitious product with a rel-5 atively large number ofinternal air cells or spaces of appreciable size whereby to not onlylighten the product but to render the same in efl'ect substantiallysimilar to the usual hollow blocks used for example largely in buildingpurposes. As distinguished from the prior process wherein such airspaces are specifically molded into the arhole, the present process aimsto secure this result by the generation of during the mixing of thecement which gas in its attempt to reach the surface of the articleforms a large number of air cells or spaces with the effect tomaterially lighten the product and at the same time form the requisitehollow air spaces in the interior of the product.

In carrying out. the process the cementitious material. preferably ingranulated form, is mixed with an a lou. and a metallic element with thelatter of the nature to be attached b the former for the generation ofgas. After being appropriately mixed, during which the gas is liberated,the mixture is placed in appropriate molds and allowed to harden. Arather important step in connection with the process is that employed tomaintaig more or less uniformity in the size ot the s aces within thearticle due to the gas bubb les. it has been found in practice that itpermitted to stand uicscent. the size gi the gas bubbles will natural lyi ne r;e ase toward the surface of the block incidentio t he decreasingpressurg of the nass, and that, assuihing it desirable to have these airvoids of substantially uniform size through- PROCESS OF PRODUCING APOROUS CEMENTITIOUS AIIRIJEIGLEJK mixed.

PATENT OFFICE.

Application filed January 4, 1926. Serial No. 79,265.

Examiner out the block, it has been found of importance to graduall turnthe block or mass of molded mater a curing temsetting operatlon, this atonce compels a mogggnless uniformity in the size o f tl 1 e ga s bubblesand thiis' the'v'oids in the mass are substan- 864 cu ic inc es 0 cubicinches of san l1 drated lime, and 2 7 aluminum. Kpproximately 7 gallonsof water are added and the mass thoroughly The process of the presentinvention is tog cubic inches of liberates a asin large quantities sothat 0 the mixed mass is m a process of ebulhtlon.

While in this state the mass is poured into the desired molds. Itallowed to set under these conditions the mass when set will be found tocontain a large number of air spaces distributed irregularly throughoutthe mass, but peculiar in that they are of smallest size at the centerof the mass and of gradually increasing size toward the surface of themass. If it be desired, as is generally the case, that these airchambers be of substantially uniform size throughout the mass it isnecessary to gradually turn or reverse the mass during the settingopera-- tion. This can be accomplished'in any manner, either by hand ormechanically, and when carried out will be found to insure adistribution of the gas bubbles throughout the mass of more or lessuniform diameter.

Of course under these circumstances, the

mass may be turned in any desired direction as for example, continuouslyon its longitudinal axis to thereby insure a uniformity in the voidsprovided by the gas bubbles.

While the process can be efliciently carried out with the use of c o ldw a t er, and may readily be varied in utense ofnew gas liberatingmaterials which will not deletepiousgly itltl'ectl the final product, ithas been 1 min t at tie use 0 arm water, say at about 129 degrees F.willmaterially accelerate theac'tion and insure a greater volume of gasin the same period ot time as compared with cold water. Therefore wherean ordinary porous mass is to be produced,

cold water may be used, while if an unusual or high degree of porosityin the mass is required, warm water will be found more effective.Furthermore, with the use of warm water and consequent increased gasliberation, the mass should he placed in the molds in a shorter timeafter mixing than is necessary with the use of cold water.

The process provides merely throughout the mixing of the up ropriateingredients and the gradual reversing of the mass during setting acomparatively light highly porous cementitious roduct, which is adaptedfor all uses in which the usual hollow cement structures are used, theproducts having the advantage that they be readily divided into desiredforms without the labor incident to the chiseling of the conventionalcementi- 6 tious product, as is now required.

I claim: The process of producing a porous cementitious articleconsisting in mixingicement In granulated form, hydrated lime, 20

formation of substantial uniform voids in 25 the mass to the gas passagetherethrough.

In testimony whereof I attix my signature.

ALEXANDER T. SCHENCK.

